@Dave999: I've used OS4's multitasking for half-a-day on my 3GS (iPhone 4 is 30% faster than 3GS)... some notes: - On apps that support OS4.0, it works very well. - I ran GPS logging/tracking in the background for a couple of hours. For all intent and purposes, the GPS tracking app (motion-x) looks and behaves as if it runs fully in the background and didn't skip a beat when switched in/out from. Unfortunately battery drain was still quite noticable - The UI is optimized to juggle between 4-8 apps. The task switcher shows 4 icons in a (horizontal) row at a time, and you can swipe to see the next 4 in one gesture. It works very fast if you juggle less than 8 apps. More than that, I think it takes a bit longer to hunt and peck. - Apps that don't support OS4.0 are made to act like they're compatible; they show up in the task-switcher icons listing, yet they're slower to switch in/out from because they don't take advantage of 'fast app switching' feature. This sucks. I wish they just close and not appear as 'active task'. (I heard there'll be a mod to take care of this, jailbreak needed of course). - I really like the folders management. It's very quick to create/delete/populate.